油包水型电火花成形加工乳化液流变特性研究

Research on the Rheology of Water-in-oil Emulsion Used in Sinking Electro-discharge Machining

开发出一种绿色环保的油包水型电火花成形加工乳化液,该种乳化液可以替代煤油用于电火花成形加工领域。采用显微观测和流变测量的方法,研究乳化液水的体积分数和温度变化对其微观结构及流变特性的影响规律关系。流变测量结果显示,随着水的体积分数的增大,乳化液的粘度呈指数上升趋势,且乳化液逐渐由牛顿流体向非牛顿流体转变;而随着温度的升高,乳化液粘度又大大降低,当温度超过约40℃时,乳化液又由非牛顿流体转变为牛顿流体,此高温低粘特性适合于电火花加工冲液的要求。加工试验表明,此油包水型电火花工作液具有与煤油基工作液相当的材料去除率,且工作环境较煤油基工作液有较大改善。本研究为电火花成形加工实现制造绿色化奠定了一定的理论与技术基础。

An environment-friendly dielectric fluid which can be an alternative to kerosene oil in electro-discharge machining（EDM） application is developed.It is water-in-oil emulsion.The effects of the change of water volume fraction and temperature on the microstructure and rheological property of the emulsion are experimentally studied by means of microscopy and rheological measurement.The results show that the viscosity of the emulsion increases exponentially with the increase of water volume fraction,and the emulsion turns from Newtonian fluid to non-Newtonian fluid gradually.However,with rising temperature the viscosity of the emulsion reduces enormously and when the temperature exceeds about 40℃,the emulsion will turn from non-Newtonian to Newtonian fluid.The character of low viscosity at high temperature is very suitable for the flushing requirement in die-sinking EDM.The experiment shows that the material removal rate with the use of the water-in-oil emulsion is as high as that of kerosene-based dielectric fluid,while the working environment is improved significantly in comparison to that of kerosene-based dielectric fluid.The research lays a theoretical and technological foundation for the EDM to realize green manufacturing.